One of the most important features of power constrained wireless network devices is their lifetime, which in turn dictates the lifetime of the network. A wireless node's lifetime depends on how the node's available energy resources (for example, its battery capacity) are exploited during the node's operation.
Conventional approaches for increasing the lifetime of a wireless network are predominantly oriented to routing as a tool to improve the network lifetime, i.e. they determine routes which require the least energy for data transmission when each wireless node is allocated a certain amount of energy for communication. For example, the problem of network lifetime can be defined as a maximization problem in terms of routing. A heuristic approach may be used to solve the optimization problem, or alternatively, distributed algorithms may be considered. The network lifetime may also be addressed in an analytical fashion including cross-layer design factors.
Another approach for relaying strategies is credit-based or reputation-based relaying, where the decisions to forward another node's packet or to use another node to forward the node's own packets are based on some type of credit payments/receipts or reputation building. However, this type of system has a drawback in that a mechanism (i.e. Trusted Party) for keeping track of and enforcing the credit/reputation decisions is required.
It follows that there is a continuing need to optimise device operation and network design in order to maximize the network lifetime subject to the limited energy resources available to each node.